Air Leak Question

Topic: Air Leak Question (Read 1035 times) previous topic - next topic

Air Leak Question

February 25, 2020, 11:19:26 am

Ready to leave Thur AM. Got everything fired up, filled up, etc. Won't build pressure. I know I have a couple of small leaks that I keep trying to find. Who doesn't? But it will always build pressure and has no issue other than losing level and running the 12v pump.
Hear it blowing air back by the engine. I am not an air system expert. And did not want to get more than my arm under there. I can live without an arm...

Blowing air out of the black tube. What is it and how do I fix it? Thank you in advance.

Re: Air Leak Question

Reply #1 – February 25, 2020, 11:22:39 am

That is your crankcase vent tube, nothing to do with your air loss. Probably the D-2 governor failure is what your are experiencing.

Re: Air Leak Question

Reply #2 – February 25, 2020, 11:25:13 am

When mine did it, it was the air dryer. Luckily I was at the Grandvention. I got Mark to fix it. Was glad he was there.

Mike

Re: Air Leak Question

Reply #3 – February 25, 2020, 11:36:06 am

This is just a not-too-likely WAG:

Is your D2 governor located on the same side of the engine shown in your photo? There is a braided air line that runs from the wet tank to the D2. It should be at the same pressure as the wet tank. IF it runs right above the area shown in your photo, and IF it had a large leak, you might feel the air stream blowing out of it. A big leak in that hose could keep the air pressure from building.

Like I said: WAG

Re: Air Leak Question

Reply #4 – February 25, 2020, 11:50:48 am

The dryer and governor is on the other side on out 320.
John M.

Re: Air Leak Question

Reply #5 – February 25, 2020, 11:54:25 am

Thanx, John.

So, disregard my WAG.

Re: Air Leak Question

Reply #6 – February 25, 2020, 12:29:38 pm

So the look of air mist and the sound seemed to be coming from that tube when I was laying next to and under the side. That tube goes to the top of the engine.
I pulled the bed cover up and the air is actually coming from this other part. I can build no pressure at all.

Re: Air Leak Question

Reply #7 – February 25, 2020, 12:36:29 pm

Looks like the D2 governer

Re: Air Leak Question

Reply #8 – February 25, 2020, 12:48:31 pm

Quote from: coastalbuilder – February 25, 2020, 12:29:38 pm

So the look of air mist and the sound seemed to be coming from that tube when I was laying next to and under the side. That tube goes to the top of the engine.
I pulled the bed cover up and the air is actually coming from this other part. I can build no pressure at all.

That is the D2 Governor and is readily available. Keep track of which air line goes where.
You need a new D2.

Re: Air Leak Question

Reply #9 – February 25, 2020, 12:50:16 pm

Awesome. Calling around now. Thank you.

Re: Air Leak Question

Reply #10 – February 25, 2020, 01:13:58 pm

Also keep track of where each plug goes. The new one will come with new plugs. If you want to be proactive buy 2 and set the plugs up in the new one so that it can be changed out quickly. They fail common enough to carry a spare.

Re: Air Leak Question

Reply #11 – February 25, 2020, 01:14:13 pm

Information for future reference.

The air is coming out the D2 exhaust port.

Air is supposed to come out there at certain times, but not all the time.

Link below to diagram and "How It Works". Good reading.

As advised by Old Toolmaker, make careful note of which air line connects where before you remove the old one.

Haldex D2 Governor Service Data

Re: Air Leak Question

Reply #12 – February 25, 2020, 02:32:39 pm

New D2 Governor installed. New governor still has air blowing out exhaust port and no pressure building. Any ideas?

Re: Air Leak Question

Reply #13 – February 25, 2020, 02:47:43 pm

Stuck unloader valve in the compressor. Take the governor back off and spray Corrosion X or any product similar, Liquid Wrench etc. into the port where the governor went. Sometimes that will get it going without a compressor change out.

This assumes you have all the ports matched up as the old D-2 had.

Re: Air Leak Question

Reply #14 – February 25, 2020, 04:02:20 pm

Quote from: craneman – February 25, 2020, 02:47:43 pm

Stuck unloader valve in the compressor. Take the governor back off and spray Corrosion X or any product similar, Liquid Wrench etc. into the port where the governor went. Sometimes that will get it going without a compressor change out.

This assumes you have all the ports matched up as the old D-2 had.

Can you pull the head and service the unloader valve?

Re: Air Leak Question

Reply #15 – February 25, 2020, 04:05:40 pm

Pulled the governor and sprayed with pb blaster. No air building.
Changed to a Haldex D2 governor. No air building.
The line going to the one side of the governor has air building in it when I take it off it has pressure.
Air dryer has constant air coming out the bottom. Bad air dryer?
Haldex DA33100X?

Re: Air Leak Question

Reply #16 – February 25, 2020, 04:47:22 pm

I just saw this thread. Air is not supposed to be coming out of the bottom of the dryer constantly. Only when the governor cuts out and a for a short time after that. A big blast at first and they a slow amount of air for a short period. Something wrong with the dryer. It can be rebuilt or replaced. Once again make sure the hoses are reattached correctly. Has an electrical connection for a heating element as well, or at least mine does.

Re: Air Leak Question

Reply #17 – February 25, 2020, 05:16:12 pm

Dryer purge stuck open. Spray it with lube a give it a light tap. Then order a new one .

Re: Air Leak Question

Reply #18 – February 25, 2020, 05:17:49 pm

Quote from: coastalbuilder – February 25, 2020, 04:05:40 pm

Air dryer has constant air coming out the bottom. Bad air dryer?

OK, so the air dryer purge valve is stuck open, allowing air to escape out the bottom of the dryer.

The air pressure from the air compressor is escaping out the bottom of the dryer instead of going to the wet tank.

Since the wet tank is not building any air pressure, it is never sending the pressure down the air line to the D2.

The D2 does not get the pressure signal from the wet tank, so the piston inside does not move.

If the piston in the D2 does not move, it don't work.

D2 (either of the new ones) is probably fine - it is just waiting on the proper signal to do its thing.

Solution: Either replace the whole dryer with new or manufacturer rebuilt, OR, on some dryers the purge valve can be rebuilt with a kit.

Re: Air Leak Question

Reply #19 – February 25, 2020, 05:38:55 pm

Thanks. Coach-net called... Hopefully they will bring a replacement dryer in the morning.
I have too many other obligations and have already spent more time than I have on this.
Thank you all for the support. I can change a governor with my eyes closed now.

Re: Air Leak Question

Reply #20 – February 25, 2020, 05:47:43 pm

We were on a trip one time, when the purge valve on our dryer started leaking badly. We happened to be parked in a Walmart parking lot in Price, UT about 100 yards away from a NAPA store. I walked over to the store, talked to the manager (only employee) and he ordered me a rebuilt dryer out of Provo. Next morning I picked up the dryer. Didn't really feel like doing the complete dryer swap in the Walmart parking lot. I looked at the fresh rebuilt dryer and saw that the purge valve was only held on with 3 bolts. So I removed the purge valve from the fresh dryer and swapped it out for the leaking valve on my old dryer. Took about 30 minutes total and I didn't even break a sweat. Went on our way - completed our trip with no further incident. When we got home I swapped out the dryers and returned our core to the local NAPA for a refund.

Re: Air Leak Question

Reply #21 – February 25, 2020, 11:52:11 pm

Not related to fixing this air leak, but it did remind me about protecting D2 exhaust port from water & dirt.

Screwed in a new brass fitting with hose brad with long open ended hose pointed down to let air out without letting debris to enter the empty D2 hole.

Re: Air Leak Question

Reply #22 – February 26, 2020, 04:38:10 pm

New remanufactured Haldex DA33100X installed. New hose installed to replace the one I twisted off.
It now builds pressure and holds pressure. I actually think it was slow leaking for while as it has held pressure at over 100PSI for 3 hours now. It never did that before.
Price Reference:
Triple T Trucks charged $266.09 plus a $120 core charge for the Haldex DA33100X
Advanced Maintenance charged 3 hours at $105/hr plus parts for $378.46.
And I now have an extra D2 governor with plugs already installed to keep on board.
Thank you all for your help.

Re: Air Leak Question

Reply #23 – February 26, 2020, 04:48:20 pm

Quote from: coastalbuilder – February 26, 2020, 04:38:10 pm

And I now have an extra D2 governor with plugs already installed to keep on board.
Thank you all for your help.

A spare D-2 Governor is a good thing to have, if you can find it when it's needed

Congratulations!

Re: Air Leak Question

Reply #24 – February 26, 2020, 05:44:38 pm

Glad to hear you are back on the road.

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